<html>
  <head>
    <script type="application/javascript">
      function draw() {
        var canvas = document.getElementById("canvas");
        if (canvas.getContext) {
          var ctx = canvas.getContext("2d");
          ctx.fillRect(25, 25, 100, 100);
          ctx.clearRect(45, 45, 60, 60);
          ctx.strokeRect(50, 50, 50, 50);
        }
      }
    </script>
  </head>
  <body onload="draw();">
    <canvas id="canvas" width="150" height="150"></canvas>
  </body>
</html>
